Worst case, lets say your forgot your piece of paper...Why is not just providing your conservation ID enough? (One can scribble that number on anything and keep it with you.) Can't the DEP officers verify the licence number in the field?
Along the same lines...what's the DEP's stance on:
Licence replication/alteration (ie. shrunk to fit in your wallet?)
or as Murph mentioned, digital storage? (Iphone licence, etc.)
Basically all of the above is just another way of providing one key bit of info...the conservation ID.
This is what I did - (shrunk, signed and laminated)
Would an officer have issues with shrinkage?